Attachments incorporating explosive bolts or the like



ec. 10, 1957 R. a. BURROWS AIIACI-IMENTS INCORPORATING EXPLOSIVE BOLTSOR THE LIKE Filed Nov. 17, 1953 IN VFNToR K )2], Xian/M 5f 15; xy/alimATTACHlVlENTS INCORPORATING EXPLOSIVE BOLTS OR THE LIKE ApplicationNovember 17, 1953, Serial No. 392,669

Claims priority, application Great Britain December 22, 1952 2 Claims.(Cl. 89-15) The invention is concerned with explosive bolts and likefastenings, such for example as are used for the attachment of twomembers which are intended to be disconnected at a given time and forwhich purpose the bolts or the like are adapted to be exploded (by thedet onation or ignition of an explosive charge contained there in) sothat by the rupture and disintegration of the bolts said members arefree to separate. In certain circumstances it is desirable to providemeans whereby two attached members may not only be rendered free toseparate but positively displaced in relation to each other. An instanceof such circumstances exists in the case of the attachments used tosecure the escape hatches or covers of the control cabins in certainaircraft. Explosive bolts have been proposed for attaching such hatches,but where the suctional elfect of the airstream is insuflicient toensure that the hatch is carried away when the bolts are exploded, meansfor its positive displacement are required. The present inventionaccordingly, has for its object to provide, in conjunction with anexplosive bolt, stud or the like, means whereby the force due to theexplosion is effective to impart a positive displacing impetus whichwill sunder the parts connected and ensure the removal of the attachedobject.

According to the invention, an attachment for the said purposecomprises, in combination with an explosive charge and means forigniting or detonating the latter, a constricted chamber housing saidcharge, a cylinder constituted by or communicating directly with saidchamber, a piston having a working fit in said cylinder, and means foraifixing said chamber (or a member associated therewith) and said pistonrespectively to the attached objects, the arrangement being such thatwhen said charge is exploded the pressure of the expanding gases thengenerated is exerted on said piston to drive the latter forcibly out ofthe cylinder and thereby to effect the physical separation of thechamber and the piston, and, consequently, of the attached objects.

The explosive charge, in the form of a cartridge, containing a detonatorhaving electrical leads connected thereto, may be enclosed within abolt-like member, the outer end of which is adapted to be affixed to oneof the parts to be attached. The said member may be so profiled as toform a piston capable of being received in a cylindrical portion of abracket which is adapted to be afiixed to the other of the parts to beattached.

The manner in which the invention may be carried into effect ishereinafter described in greater detail with reference to theaccompanying drawings, which illustrate the application of the inventionto three alternative forms of explosive bolt attachments such as aresuitable for fixing a panel of the skin of an aircraft structure, suchas the cover or hatch of the cockpit or other compartment. In saiddrawings Fig. 1 is an axial section of one form of attachment and Fig. 2is a plan thereof as seen from the interior of the structure. Figs. 3and 4 are similar 2,815,698 Patented Dec. 10, 1957 views to Fig. 1,respectively illustrating two alternative embodiments of the invention.

It is an essential condition of the device provided by this inventionthat it should provide for the positive outward displacement of thecover, batch or the like when the bolts which ordinarily secure thelatter in position are exploded, e. g. in an emergency requiring thepilots escape through the hatch opening. It will be seen that the threeembodiments herein described possess two components common to all, viz.a bracket 10 which is suitably attached to the cabin structure or frameof the aircraft, of which part is seen at 11, said bracket 10 carryingan off-set body 12 which encloses in a cylinder the piston hereinafterreferred to, and a bolt-like member 13 which is attached at its outerend to the plating 14 or other part of the removable hatch or cover.

The body 12 is bored axially to form a cylinder 121 in which the member13 is received, the latter having a shank 131 which extends through andprojects beyond the inner end of the body 12 when the cover 14 is inposition, so that it may be held securely by means of a nut 15 screwedon said shank.

The member 13 is also fashioned with a circumferentially formed shoulderor land 132 which fits the bore of the cylinder 121 of the body 12 so asto constitute a piston which will be subjected to the pressure withinthe space 122.

The shank 131 of the member 13 is also bored from the inner end to forma chamber 133 in which is stowed an explosive cartridge 16, the electricleads 17 connected to which pass out through the end of the shank 131 tothe usual circuit connections.

The arrangement is such that, in the event of an emergency necessitatingthe removal of the panel 14, the cartridges 16 of the several boltsholding the same are simultaneously detonated. The bolts are therebyfractured in the region of the space 122 and the pressure of theexpanding gases in the space 122 imparts to the respective pistons 132an ejective force which is effective to drive the same out of theircylinders 121, displacing the panel 14 laterally into the airstreamsufiiciently to ensure its being carried away clear of the aircraftstructure.

This device may also be used to detach instruments or package containersWhere it is essential to clear projecting aircraft structure, while theprecise timing inherent in the device makes it suitable for droppingflares or the like in a restricted area. It is not subject to the icingtroubles associated with the normal bomb slip when mounted externally inthe airstream.

In the arrangement shown in Fig. 1, it Will be seen that a considerabledegree of clearance is provided between the shoulder or land 132 and thebore of the cylinder 121, the purpose of which is to reduce shock at theinstant of explosion. The reduced diameter of the member 13 at its outerextremity is intended to permit a certain degree of lateral movement ofthe panel 14 on detachment.

Where the panel 14 is required to sustain shear loads in normal use, i.e. when in situ, these may be transmitted between the structure member11 and the panel 14 through the medium either of a plug-like land 134 onthe member 13, as shown in Fig. 2, or of a spigot 141 affixed to thepanel 14 itself, as shown in Fig. 3. Both the land 13 and the spigot 141are arranged to fit closely in the end of the cylinder 12.

What I claim as my invention and desire to secure by Letters Patent is:

1. The combination of a pair of separate generally flat members and anexplosive bolt mechanism normally securing said members in adjoiningsubstantially coplanar relationship, but capable of forcibly separatingsaid mem- 3 H bers and urging them into difierent planes, saidmechanisfn comprising a housing body; means fixedly connecting said bodyto one said member in overlying relation totheiotherosaid member,and1wholly on one side of the common plane of said members,'-said: bodybeingYfQnnedM With! a' bore opening toward and covered by-the other saidmember, :a--pistom withini said bore fixedly-{connected tosaid-other-rmember= and-disposed wholly on.saidone-side of Abe; commonplaneof the= members; :a frangible i connectionbtween: said piston andsaidbodynonmally-fixedly secuning saidl pistom in said bore, andexplosive means in said here. for, breakin gsaid? connection? and. 1forcibly v ejecting-;saidzpiston through the=open end of-- theibore 2..-The combination ofa-a-pain of.separateefiatemembersz and anexplosive-bolt mechanism i normally :seeuringsaid its open end, a pistonoperatively disposed in said bore for ejection thfoughits open endjfafrangible" connection between said piston and saidlibody, saidconnection normally fixedly retaining the piston in said bore, explosivemeans in said bore for breakingisaid frangible connection and forciblyejecting said piston from the open end of the bore; saidottieemember*exgendingbverthe*open'end of said bore inthepathofejecti'oirofsaid piston, and

means extending throughlthewopeniendlbfvthe :bow and' connectings'aidrpistomtoi said othewmemben References Cited in the file ofthisrpatent UNITED STATE'S" PATENT

